82 research outputs found
Molecular Identification of Six Honeybee Viruses in Iranian Apiaries
The identification of honeybee viruses is of serious importance, particularly considering the lack of information on the natural incidence of viral infections in honeybee populations worldwide. Moreover, the global spread of Varroa destructor in honeybee colonies has a significant effect on the viral infection. In the present study, 160 samples of adult bee from apparently healthy colonies but with a background of parasitic diseases, tremor, and paralysis, were collected during 2011-2012. The samples belonged to 23 different provinces of Iran. They were sent to Razi Vaccine and Serum Research Institute, Karaj, Iran, for further analysis, and examined for the presence of viruses using reverse transcription polymerase chain reaction assay. According to the results, out of 160 samples, 9 (5.8 %), 40 (25.6 %), 12 (7.8 %), 34 (21.8 %), 7 (4.5 %), and 29 (18.5%) cases were positive for acute bee paralysis virus (ABPV), black queen cell virus (BQCV), chronic bee paralysis virus (CBPV), deformed wing virus (DWV), Kashmir bee virus (KBV), and sacbrood virus (SBV). The samples collected from 18 provinces (78 %) were positive for at least one virus. Among all samples, 83 (53.2 %) specimens were infected with at least one virus. The highest prevalent virus was BQCV, followed by DWV, SBV, CBPV, ABPV, and KBV, respectively
Network Intrusion Detection with Limited Labeled Data
With the increasing dependency of daily life over computer networks, the
importance of these networks security becomes prominent. Different intrusion
attacks to networks have been designed and the attackers are working on
improving them. Thus the ability to detect intrusion with limited number of
labeled data is desirable to provide networks with higher level of security. In
this paper we design an intrusion detection system based on a deep neural
network. The proposed system is based on self-supervised contrastive learning
where a huge amount of unlabeled data can be used to generate informative
representation suitable for various downstream tasks with limited number of
labeled data. Using different experiments, we have shown that the proposed
system presents an accuracy of 94.05% over the UNSW-NB15 dataset, an
improvement of 4.22% in comparison to previous method based on self-supervised
learning. Our simulations have also shown impressive results when the size of
labeled training data is limited. The performance of the resulting Encoder
Block trained on UNSW-NB15 dataset has also been tested on other datasets for
representation extraction which shows competitive results in downstream tasks
GJ 357 b: A Super-Earth Orbiting an Extremely Inactive Host Star
In this paper we present a deep X-ray observation of the nearby M dwarf GJ
357 and use it to put constraints on the atmospheric evolution of its planet,
GJ 357 b. We also analyse the systematic errors in the stellar parameters of GJ
357 in order to see how they affect the perceived planetary properties. We
estimate the age of GJ 357 b by comparing the observed X-ray luminosity of its
host star, derived from a recent {\em XMM-Newton} observation {(), with age relations for M dwarfs. We
find that GJ 357 presents one of the lowest X-ray activity levels ever measured
for an M dwarf, and we put a lower limit on its age of \,Gyr.} Using this
age limit, we perform a backwards reconstruction of the original primordial
atmospheric reservoir. Furthermore, by considering the systematic errors in the
stellar parameters, we find a range of possible planetary masses, radii, and
densities. From the backwards reconstruction of GJ 357 b's irradiation history
we find that the upper limit of its initial primordial atmospheric mass is
. An initial atmospheric reservoir significantly larger
than this may have survived through the X-ray and ultraviolet irradiation
history, hence being inconsistent with current observations that suggest a
telluric composition. In spite of the unlikelihood of a currently existing
primordial envelope, volcanism and outgassing may have contributed to a
secondary atmosphere. Under this assumption, we present three different
synthetic infrared spectra for GJ 357 b that one might expect, consisting of
, , and , and .Comment: Accepted for publication in A&
Constraints on the mass and atmospheric composition and evolution of the low-density young planet DS Tuc A b
We performed a radial velocity (RV) monitoring of the 40 Myr old star DS Tuc
A with HARPS at the ESO-3.6m to determine the planetary mass of its 8.14-days
planet, first revealed by TESS. We also observed two planetary transits with
HARPS and ESPRESSO at ESO-VLT, to measure the Rossiter-McLaughlin (RM) effect
and characterise the planetary atmosphere. We measured the high-energy emission
of the host with XMM observations to investigate models for atmospheric
evaporation. We employed Gaussian Processes (GP) regression to model the high
level of the stellar activity, which is more than 40 times larger than the
expected RV planetary signal. We extracted the transmission spectrum of DS Tuc
A b from the ESPRESSO data and searched for atmospheric elements/molecules
either by single-line retrieval and by performing cross-correlation with a set
of theoretical templates. Through a set of simulations, we evaluated different
scenarios for the atmospheric photo-evaporation of the planet induced by the
strong XUV stellar irradiation. While the stellar activity prevented us from
obtaining a clear detection of the planetary signal from the RVs, we set a
robust mass upper limit of 14.4 M_e for DS Tuc A b. We also confirm that the
planetary system is almost (but not perfectly) aligned. The strong level of
stellar activity hampers the detection of any atmospheric compounds, in line
with other studies presented in the literature. The expected evolution of DS
Tuc A b from our grid of models indicates that the planetary radius after the
photo-evaporation phase will fall within the Fulton gap. The comparison of the
available parameters of known young transiting planets with the distribution of
their mature counterpart confirms that the former are characterised by a low
density, with DS Tuc A b being one of the less dense.Comment: 24 pages, 19 figures, Accepted for publication on Astronomy and
Astrophysic
ARES. III. Unveiling the Two Faces of KELT-7 b with HST WFC3*
We present the analysis of the hot-Jupiter KELT-7 b using transmission and emission spectroscopy from the Hubble Space Telescope, both taken with the Wide Field Camera 3. Our study uncovers a rich transmission spectrum that is consistent with a cloud-free atmosphere and suggests the presence of H_{2}O and H^{−}. In contrast, the extracted emission spectrum does not contain strong absorption features and, although it is not consistent with a simple blackbody, it can be explained by a varying temperature–pressure profile, collision induced absorption, and H^{-}. KELT-7 b had also been studied with other space-based instruments and we explore the effects of introducing these additional data sets. Further observations with Hubble, or the next generation of space-based telescopes, are needed to allow for the optical opacity source in transmission to be confirmed and for molecular features to be disentangled in emission
Acute escitalopram treatment inhibits REM sleep rebound and activation of MCH-expressing neurons in the lateral hypothalamus after long term selective REM sleep deprivation.
RATIONALE: Selective rapid eye movement sleep (REMS) deprivation using the platform-on-water ("flower pot") method causes sleep rebound with increased REMS, decreased REMS latency, and activation of the melanin-concentrating hormone (MCH) expressing neurons in the hypothalamus. MCH is implicated in the pathomechanism of depression regarding its influence on mood, feeding behavior, and REMS. OBJECTIVES: We investigated the effects of the most selective serotonin reuptake inhibitor escitalopram on sleep rebound following REMS deprivation and, in parallel, on the activation of MCH-containing neurons. METHODS: Escitalopram or vehicle (10 mg/kg, intraperitoneally) was administered to REMS-deprived (72 h) or home cage male Wistar rats. During the 3-h-long "rebound sleep", electroencephalography was recorded, followed by an MCH/Fos double immunohistochemistry. RESULTS: During REMS rebound, the time spent in REMS and the number of MCH/Fos double-labeled neurons in the lateral hypothalamus increased markedly, and REMS latency showed a significant decrease. All these effects of REMS deprivation were significantly attenuated by escitalopram treatment. Besides the REMS-suppressing effects, escitalopram caused an increase in amount of and decrease in latency of slow wave sleep during the rebound. CONCLUSIONS: These results show that despite the high REMS pressure caused by REMS deprivation procedure, escitalopram has the ability to suppress REMS rebound, as well as to diminish the activation of MCH-containing neurons, in parallel. Escitalopram caused a shift from REMS to slow wave sleep during the rebound. Furthermore, these data point to the potential connection between the serotonergic system and MCH in sleep regulation, which can be relevant in depression and in other mood disorders
Cascade of Neural Events Leading from Error Commission to Subsequent Awareness Revealed Using EEG Source Imaging
The goal of the present study was to shed light on the respective contributions of three important action monitoring brain regions (i.e. cingulate cortex, insula, and orbitofrontal cortex) during the conscious detection of response errors. To this end, fourteen healthy adults performed a speeded Go/Nogo task comprising Nogo trials of varying levels of difficulty, designed to elicit aware and unaware errors. Error awareness was indicated by participants with a second key press after the target key press. Meanwhile, electromyogram (EMG) from the response hand was recorded in addition to high-density scalp electroencephalogram (EEG). In the EMG-locked grand averages, aware errors clearly elicited an error-related negativity (ERN) reflecting error detection, and a later error positivity (Pe) reflecting conscious error awareness. However, no Pe was recorded after unaware errors or hits. These results are in line with previous studies suggesting that error awareness is associated with generation of the Pe. Source localisation results confirmed that the posterior cingulate motor area was the main generator of the ERN. However, inverse solution results also point to the involvement of the left posterior insula during the time interval of the Pe, and hence error awareness. Moreover, consecutive to this insular activity, the right orbitofrontal cortex (OFC) was activated in response to aware and unaware errors but not in response to hits, consistent with the implication of this area in the evaluation of the value of an error. These results reveal a precise sequence of activations in these three non-overlapping brain regions following error commission, enabling a progressive differentiation between aware and unaware errors as a function of time elapsed, thanks to the involvement first of interoceptive or proprioceptive processes (left insula), later leading to the detection of a breach in the prepotent response mode (right OFC)
Circuit-based interrogation of sleep control.
Sleep is a fundamental biological process observed widely in the animal kingdom, but the neural circuits generating sleep remain poorly understood. Understanding the brain mechanisms controlling sleep requires the identification of key neurons in the control circuits and mapping of their synaptic connections. Technical innovations over the past decade have greatly facilitated dissection of the sleep circuits. This has set the stage for understanding how a variety of environmental and physiological factors influence sleep. The ability to initiate and terminate sleep on command will also help us to elucidate its functions within and beyond the brain
Enabling planetary science across light-years. Ariel Definition Study Report
Ariel, the Atmospheric Remote-sensing Infrared Exoplanet Large-survey, was adopted as the fourth medium-class mission in ESA's Cosmic Vision programme to be launched in 2029. During its 4-year mission, Ariel will study what exoplanets are made of, how they formed and how they evolve, by surveying a diverse sample of about 1000 extrasolar planets, simultaneously in visible and infrared wavelengths. It is the first mission dedicated to measuring the chemical composition and thermal structures of hundreds of transiting exoplanets, enabling planetary science far beyond the boundaries of the Solar System. The payload consists of an off-axis Cassegrain telescope (primary mirror 1100 mm x 730 mm ellipse) and two separate instruments (FGS and AIRS) covering simultaneously 0.5-7.8 micron spectral range. The satellite is best placed into an L2 orbit to maximise the thermal stability and the field of regard. The payload module is passively cooled via a series of V-Groove radiators; the detectors for the AIRS are the only items that require active cooling via an active Ne JT cooler. The Ariel payload is developed by a consortium of more than 50 institutes from 16 ESA countries, which include the UK, France, Italy, Belgium, Poland, Spain, Austria, Denmark, Ireland, Portugal, Czech Republic, Hungary, the Netherlands, Sweden, Norway, Estonia, and a NASA contribution
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